The influence of maize-winter wheat rotation and pre-emergence herbicides on weeds and maize productivity

Crop rotation is a simple and effective part of an Integrated Weed Management (IWM) system. This approach makes it possible to rotate herbicides with different modes of action (MOA), avoiding or postponing herbicide resistance. Besides all the known advantages and benefits, it is still not widely used in maize (Zea mays L.) production. In Serbia, about 20% of total maize production is a continuous cropping. The aim of this research was to test the benefits of growing maize in crop rotation with winter wheat (Triticum vulgare L.) compared with a continuous cropping, combined with pre-emergence herbicide application. Field trials started in 2009, and five maize-winter wheat rotations have been completed. Weeds were controlled with a herbicide mixture of isoxaflutole and S-metolachlor, applied at either the full label rate or half rate, while one plot was kept weed free (manually), and one was a control. Integrating crop rotation and PRE herbicides decreased the biomass of weeds and their density by 98% and 99%, respectively. In continuous maize, perennial weeds became dominant after the first rotation. Crop rotation significantly influenced maize productive parameters, decreasing the variation in leaf area index and grain yield, increasing values with the number of cycles. The biggest differences in the analyzed parameters were observed in 2015, 2017 and 2019, indicating many positive long-term benefits of crop rotation on maize leaf area index and grain yield.